1. Technical Field of the Invention
The present invention relates to a vacuum processing apparatus in which an objects to be processed, such as a semiconductor wafer, is processed in a vacuum atmosphere in a semiconductor manufacturing process or the like.
2. Description of the Related Art
In the semiconductor manufacturing process, the semiconductor wafer is introduced in a processing vessel capable of forming a vacuum, so that the wafer is subjected to film-forming, etching, etc. in the vacuum atmosphere. In such a process in the vacuum atmosphere, a turbo-molecular pump is often used as a vacuum pump for producing the vacuum atmosphere.
As one structure for producing the vacuum atmosphere in the processing vessel by means of the turbo-molecular pump, there is known a plasma etching apparatus 1 shown in FIGS. 7 and 8. In order to mount a wafer W, the plasma etching apparatus 1 includes a susceptor 3 arranged in a processing vessel 2. On the underside of the susceptor 3, a driving mechanism 4 is provided for driving the susceptor 3 up and down. Further, above the susceptor 3, a shower head 5 is provided for introducing process gas, such as CF4, in the processing vessel 2. On the lateral side of the processing vessel 2, for example, two exhaust pipes 6 are connected in order to exhaust the vessel 2 thereby to form a vacuum therein.
On both sides of the processing apparatus 1, a pair of turbo-molecular pumps 10 are connected with the exhaust pipes 6, respectively. In each of the turbo-molecular pumps 10, a motor stator 11 is provided for a center shaft of the pump 10 and a motor rotor 13 is rotatably arranged about the motor stator 11 through a bearing 12. The motor rotor 13 is provided, on its upper portion, with a number of rotors 14 which operate to absorb the process gas downward in the molecular condition. Further, the turbo-molecular pump 10 includes a housing 15 provided with a number of stators 16.
In operation, when the motor rotors 13 of the turbo-molecular pumps 10 are rotated simultaneously, the great number of rotors 14 are also rotated against the stators 16. Consequently, the exhaust gas in the processing vessel 2 is sucked in the molecular condition via the exhaust pipes 6, so that the interior of the processing vessel 2 is maintained under a generally vacuum condition.
However, there exists a problem in the above structure where the pair of turbo-molecular pumps 10 are arranged on both sides of the processing apparatus 1 in order to form a vacuum in the processing vessel 2. The problem is that the floor area occupied by the turbo-molecular pumps 10 is too large. Therefore, it is apprehended that, with the future progress of the large diameter semiconductor wafer, the floor area occupied by the vacuum pumps is further increased thereby to cause the processing installation to be large-sized. Under such an anticipation, there is an eager demand to reduce the floor space to be occupied by the vacuum pump to the utmost.
Under such a situation, it is therefore an object of the present invention to provide a vacuum processing apparatus which is capable of minimizing the size of the whole apparatus in order to reduce the floor area to be occupied by the vacuum pump.
According to the first feature of the invention, there is provided a vacuum processing apparatus for applying a designated process on an object to be processed in a vacuum atmosphere, comprising a processing vessel for applying the designated process on the object introduced thereinto, and a vacuum pump arranged on either downside or upside the processing vessel so as to be coaxial with the processing vessel, for sucking exhaust gas in the processing vessel thereby to form a vacuum. In this way, when arranging the vacuum pump on either downside or upside of the processing vessel coaxially, then it is possible to remarkably reduce the floor area occupied by the vacuum pump in comparison with a case of arranging the vacuum pump on the lateral side of the processing vessel, whereby the whole processing apparatus can be small-sized. Therefore, even if the processing vessel is caused to be large-sized with the future large diameter object to be processed, it is possible to prevent the floor area occupied by the whole apparatus from being increased remarkably.
The second feature of the invention resides in that, in the arrangement where a susceptor for mounting the object is provided in the processing vessel, the vacuum pump is arranged below the susceptor so as to be coaxial with the processing vessel. In this case, it is possible to reduce the occupied area furthermore.
The third feature of the invention resides in that the vacuum pump is constructed cylindrically as the whole. In this case, it is possible to reduce the occupied area remarkably.
According to the fourth feature of the invention, there is provided a vacuum processing apparatus for applying a designated process on an object to be processed in a vacuum atmosphere, comprising: a processing vessel for applying the designated process on the object introduced thereinto, the processing vessel being provided, therein, with a susceptor for mounting the object thereon; a vacuum pump constructed cylindrically as a whole and arranged below the susceptor in the processing vessel so as to be coaxial with the processing vessel, for sucking exhaust gas in the processing vessel thereby to form a vacuum; and a driving mechanism arranged below the susceptor, for moving it up and down, wherein the vacuum pump is arranged around the driving mechanism coaxially therewith. In this case, since the vacuum pump is arranged around the large-sized driving mechanism, it is possible to progress the effect of reducing the occupied floor area remarkably.
The fifth feature of the invention resides in that the vacuum pump is a turbo-molecular pump.
According to the sixth feature of the invention, there is provided a vacuum processing apparatus for applying a designated process on an object to be processed in a vacuum atmosphere, comprising: a processing vessel for applying the designated process on the object introduced thereinto, the processing vessel being provided, therein, with a susceptor for mounting the object thereon; a turbo-molecular vacuum pump constructed cylindrically as a whole and arranged below the susceptor in the processing vessel so as to be coaxial with the processing vessel, for sucking exhaust gas in the processing vessel thereby to form a vacuum, the turbo-molecular vacuum pump including: a cylindrical inner housing arranged in coaxial with the processing vessel; a cylindrical motor stator arranged outside the cylindrical inner housing; a number of rotors rotatably arranged with respect to the cylindrical motor stator; a cylindrical outer housing arranged outside the rotors; and a number of stators fixed to the cylindrical outer housing so as to each extend between the adjacent rotors; and a driving mechanism arranged below the susceptor, for moving it up and down, wherein the vacuum pump is arranged around at least a portion of the driving mechanism coaxially therewith. In a conventional motor having a rotating member like a rotor, there has been no idea to provide a rotating shaft of the rotating member in the form of a cylinder and dispose another mechanism in the shaft.
The seventh feature of the invention resides in that the vacuum processing apparatus further comprises an exhaust port communicating with the vacuum pump and opening to the interior of the processing vessel, wherein the exhaust port is arranged in a floor of the processing vessel annularly and uniformly. The eighth feature of the invention resides in that the exhaust port is identical to an annular opening succeeding in the circumferential direction of the processing vessel. The ninth feature of the invention resides in that the exhaust port is constituted by a plurality of openings separated from each other in the circumferential direction of the processing vessel. In this way, owing to the arrangement where the exhaust port is formed in the circumference of the vessel about the axis, it is possible to perform the exhausting operation uniformly and quickly in comparison with a case of absorbing the gas through the lateral side of the processing vessel.
The tenth feature of the invention resides in that the exhaust port is arranged around the susceptor for mounting the substrate thereon.
The above and other features and advantages of this invention will become apparent, and the invention itself will best be understood, from a study of the following description and appended claims, with reference had to the attached drawings showing a preferred embodiment of the invention.